The present invention relates to sensors, and more particularly, this invention relates to forming optical image sensors.
Image sensors find applications in a wide variety of fields, including machine vision, robotics, astronomy, navigation, as well as consumer products. While complementary metal-oxide-semiconductor (CMOS) technology has provided the foundation for advances in low-cost, low-power, reliable, highly integrated systems for many consumer applications, charge coupled devices (CCDs) have been, until recently, the primary technology used in electronic imaging applications. CCDs, however, are high capacitance devices that require high voltage clocks, consume large amounts of power, provide only serial output, and require specialized silicon processing that is incompatible with CMOS technology. The availability of sub-micron CMOS technology and the advent of active pixel sensors (APS) have made CMOS technology more attractive for imaging applications.